Tannin in Persimmons. 11 



at this time, in a condition of turgor and the dimensions of the 

 cell wall or of the plasmatic membrane do not change, even with 

 a strong solution of the agent. The behavior toward the ferric 

 chloride, therefore, is due, I believe, to the relation of the tannin- 

 mass to the reagent, and not the cell as a whole, save of course, 

 the interference of the cell-wall to the ferric chloride molecule. 

 It is difficult to believe that tannin, as such and unassociated 

 with a carrier capable of limited imbibition, can behave in this 

 manner, (figs. 7, 8). 



The size of the tannin-mass in young and old cells has a 

 similar bearing. No matter how young the cell and how little 

 tannin it may contain (if we may believe that the depth of 

 coloring in reaction to ethyl nitrite indicates amount) the tannin- 

 mass always impinges on the protoplasm except where there 

 occur superficial pits '•= and other depressions to be accounted for 

 bv the presence of the nucleus and differences of thickness of 

 the plasma, strands of it, and, probably, sap-vacuoles independ- 

 ent of the tannin-mass(fig.l). These relations are similar in both 

 old and young cells, and do not affect the bulk of tannin-mass 

 appreciably. This constancy of size of the mass with the constant 

 increase in depth of reaction of the tannin contained in it, seems 

 to indicate that a carrier is present and that its spatial relations 

 are practically constant, while the amount of tannin is not. 



I have already, in the paper on the date above mentioned, 

 advanced an explanation for the observation made by Howard 

 and by myself, that intercellular tannin occurs, to the effect that 

 it is due to accident. Any method of treatment of a hard fruit, 

 in which the tannin-masses are still fluid, that will cause the rup- 

 ture of the tannin-cells, produces, in this way, intercellular 

 tannin. If a block of mesocarp is cvit out with a sharp knife 

 with care not to bruise the pulp, and then treated with ethyl 

 nitrite or copper acetate, the tissues to some depth below the 

 cut surfaces'will be found injected so that practically all the inter- 

 cellular spaces are occupied by the expressed tannin-mass. 

 Fruits which have been bruised always show the same thing 

 when properly prepared for examination. Superficial bruises 

 are easily detected by their brownish color, although the fruit 

 may be firm and there may be no depression at the place of 

 bruising. This change of color is explained by the coloring of the 



♦Called ''vacuoles ' by Howard. This is not an accepted usage. 



